As is well known, a double-filter-cigarette is obtained by first forming an intermediate product having a filter plug interposed between two cigarettes, and then wrapping a tip-paper piece around the intermediate product to thereby connect the two cigarettes with the filter plug. The double-filter-cigarette is then cut at its center, that is, at its filter plug portion, and formed into individual filter-cigarettes.
The double-filter-cigarette as mentioned above is formed by a filter attaching device, and such filter attaching device is disclosed, for example, in Japanese Patent Preliminary Publication No. Sho 63-196257 or Japanese Patent Preliminary Publication No. Hei 4-211355. The filter attaching device comprises a supply drum for supplying a tip-paper piece and a rolling plate. The supply drum and the rolling plate cooperate with each other, and define a rolling passage for the above mentioned intermediate product. More specifically, the rolling passage is defined by the peripheral surface of the supply drum and the upper surface, that is, the rolling surface of the rolling plate. When the intermediate product is introduced into the rolling passage, a tip-paper piece is supplied onto the peripheral surface of the intermediate product, simultaneously. One of the surfaces of the tip-paper piece is a surface to which glue has been applied. Therefore, as the intermediate product rolls on in the rolling passage, the tip-paper piece is wrapped around and glued to the intermediate product at the same time. As a result, the double-filter-cigarette as mentioned above is obtained. After the tip-paper piece is wrapped, a lap portion where both ends of the tip-paper piece overlap each other is formed.
In recent years, speed of carrying the intermediate product tends to be increased in order to improve productivity of manufacturing the filter-cigarette. In order to ensure stable wrapping of the tip-paper piece around the intermediate product, or in other words, sufficient fastening of the intermediate product by the tip-paper piece even when the intermediate product is carried at a high speed, the intermediate product is made to roll for rotations several times while the product passes through the rolling passage.
While the intermediate product passes through the rolling passage, the intermediate product is sandwiched between the supply drum and the rolling plate. Therefore, the more times the intermediate product rotates, the more the cigarettes included in the intermediate product are kneaded and loosened. Thus, the hardness of the cigarette decreases.
The formed double-filter-cigarette is then brought out of the rolling passage and carried on the carrying path on the downstream side. In this process, if the cigarettes do not have a sufficient hardness, it causes shredded tobacco's falling off both ends of the double-filter-cigarette or one ends of the filter-cigarettes. Thus, it may cause so-called accidental falling of shredded tobacco constituting a cigarette end portion.